Metalloporphyrins with several nitro groups in beta-positions were used in the epoxidation of cyclic olefins with magnesium monoperoxyphthalate (MMPP) as an oxygen atom donor, under mild conditions. Iron- and manganese-pernitrated complexes are; able to promote the epoxidation of alkenes without requiring the addition of any nitrogen base. Cobalt porphyrins showed low activity, but addition of the cocatalyst raised it.